Megasecond

For historical events in the megasecond range see timeline of modern history. For a list half-lives in this timescale, see: List of isotopes by half-life.

A megasecond (symbol: Ms) is 1 million seconds, or roughly 11.6 days. There are roughly 31.5 megaseconds in a year. This page lists times between 1 and 1000 megaseconds (10⁶ seconds and 10⁹ seconds), or 11.6 days and 31.7 years.

• shorter times

<1 year

• 14 days (1.2096 × 10⁶ s) – a fortnight
• 27.3217 days (2.3605915 × 10⁶ s) – sidereal month
• 28 days – length of February in non-leap years
• 29 days – length of February in a leap year
• 29.53059 days – mean synodic month
• 30 days (2.592 × 10⁶ s) – length of the months April, June, September, and November
• 30.436875 days (2.629746 × 10⁶ s) – mean length of a Gregorian calendar month
• 31 days – length of the months January, March, May, July, August, October, and December
• 87 days 23.3 hours (7.6 × 10⁶ s) – one orbit of Mercury
• 90 days – approximate length of a quarter year, a common corporate and financial reporting interval
• 95 days - length of Napoleon's attempt at regaining power, known as the Hundred Days
• 100 days - approximate length of the Rwandan genocide
• 224.701 days (19.4141 × 10⁶ s) — one orbit of Venus
• 260 days — length of the Tzolk'in, or Sacred Round, in the Mayan calendar
• 280 days — average length of a human pregnancy; ~24 million seconds
• 353, 354 or 355 days — the lengths of regular years in some lunisolar calendars
• 354.37 days (30.6173136 × 10⁶ s) — 12 lunar months; the average length of a year in lunar calendars
• $\pi \cdot 10^7 s$ — The value of pi times 10⁷ seconds is sometimes given as an approximate year value; it works out to 363.61026 days.
• 360 days — one tun in the Mesoamerican Long Count calendar
• 365 days — a regular year in many solar calendars; ~31.53 million seconds. Also the fixed length of the year in the Ancient Egyptian calendar and the length of a Haab in the Mayan calendar.
• 365.24219 days — a mean tropical year near the year 2000
• 365.2424 days — a vernal equinox year.
• 365.2425 days — the average length of a year in the Gregorian calendar
• 365.25 days — the average length of a year in the Julian calendar
• 365.2564 days — a sidereal year

>1 year

• 366 days — a leap year in many solar calendars; 31.62 million seconds
• 10^7.5 s — the square root of 10, times 10 million seconds = 31,622,776.6 seconds = 1.00208673 years = 366.004359 days = a leap year plus 6.27 minutes
• 383.9 days — 13 lunar months; leap year in some lunisolar calendars
• 383, 384 or 385 days — the lengths of leap years in some lunisolar calendars
• 686.971 days — one orbit of Mars
• 729 days — in Canada, the maximum prison sentence that can be served in a provincial correctional facility as opposed to a federal institution under the jurisdiction of the Correctional Service of Canada, otherwise known as "two years less a day"
• 4 years—full term of the President of the United States; (roughly) an Olympiad.
• 4 years, 42 days—duration of World War I
• 4.37 years—the length of time for light from Alpha Centauri to reach Earth
• 4.6 years—orbital period of Ceres
• 5 years—maximum length of a term in the British and Canadian Parliaments
• 6 years—full term of a Senator in the United States. Duration of World War II
• 7 years—the interval between leap seconds on December 31, 1998 and December 31, 2005, the longest one as of 2009^[update]
• 10 years—one decade = 3.16 × 10⁸ seconds
• 11 years -- sunspot activity cycle (7.5 to 11 years)
• 11.87 years—one orbit of Jupiter
• 12 years—length of one cycle through the Chinese zodiac (Terrestrial branch)
• 12.27 years—duration of Nazi Germany
• 13 years—typical time to complete K-12 education in the United States.
• 15 years—age at which one is first eligible to receive a driver's license in New Zealand.
• 16 years—usual age at which one is first eligible to receive a driver's license in most States of the United States.
• 18 years-age at which (in the United States) one is legally permitted to vote, sign contracts, and to use tobacco products.
• 18.03 years -- Saros cycle, the period of solar eclipses and lunar eclipses
• 19.0002 years—235 months (1 Metonic cycle)
• 19.713 years (7200 days) -- one katun in the Mesoamerican Long Count calendar
• 21 years—age at which one can consume alcoholic beverages in the United States.
• 29 years—recorded maximum lifespan of a dog
• 29.458 years—one orbit of Saturn
• 30.437 years-duration of the World Trade Center

• Longer times

See also

• Months
• Years
• Decades